C. Demaille et J. Moiroux, Sensing a self-assembled protein structure through its permeation by a ferrocene labeled poly(ethylene glycol) chain, J PHYS CH B, 103(45), 1999, pp. 9903-9909
Cyclic voltammetry was used for systematic analysis of the diffusion of a b
ulky mono ferrocene poly(ethylene glycol) ((PEG-Fc, MW ca, 3400 g/mol) redo
x probe through a film made of N successively self-assembled monolayers of
immunoglobulins immobilized at the electrode surface. A membrane-like model
of the film is considered. A theoretical approach is developed showing tha
t, in the general case, five parameters are involved in the control of the
process. The influence of each parameter and the possible limiting situatio
ns are discussed. Quantitative information is derived from the changes appe
aring in the experimental cyclic voltammograms when N increases and/or when
the potential scan rate is varied over 3 orders of magnitude. The PEG-Fc p
robe is bully enough to sense the presence of the IgG self-assembly. Its di
ffusion coefficient through the membrane-like film is roughly 2 orders of m
agnitude smaller than in solution. The diameter of the channels which exist
between the self-assembled IgG layers is not much larger than the 4.2 nm h
ydrodynamic diameter of the PEG coil.